This paper introduces a unified framework called cooperative extensive form games, which (i) generalizes standard non-cooperative games, and (ii) allows for more complex coalition formation dynamics than previous concepts like coalition-proof Nash equilibrium. Central to this framework is a novel solution concept called cooperative equilibrium system (CES). CES differs from Nash equilibrium in two important respects. First, a CES is immune to both unilateral and multilateral `credible' deviations. Second, unlike Nash equilibrium, whose stability relies on the assumption that the strategies of non-deviating players are held fixed, CES allows for the possibility that players may regroup and adjust their strategies in response to a deviation. The main result establishes that every cooperative extensive form game, possibly with imperfect information, possesses a CES. For games with perfect information, the proof is constructive. This framework is broadly applicable in contexts such as oligopolistic markets and dynamic political bargaining.

翻译：本文介绍了一个名为合作扩展式博弈的统一框架，该框架（i）推广了标准非合作博弈，（ii）允许比先前概念（如联盟证明纳什均衡）更复杂的联盟形成动态。该框架的核心是一种新颖的解概念——合作均衡系统（CES）。CES在两个方面与纳什均衡不同：首先，CES对单边和多边“可信”偏离均具有免疫性；其次，与稳定性依赖于非偏离者策略保持不变假设的纳什均衡不同，CES允许玩家可能重新分组并调整其策略以应对偏离。主要结果表明，每个合作扩展式博弈（可能包含不完全信息）均存在一个CES。对于完美信息博弈，该证明是构造性的。这一框架可广泛适用于寡头市场与动态政治谈判等场景。